I try to do the DFT calculations with fractional numbers of electrons using the LC-wPBE functional. I use w=0.149 and 0.177 for comparison. I decrease the total electron number from the neutral to cation with Nsize = 0.1 charge. I check the LC-wPBE(0.177) result and I notice that the increase of the total energy is too high from neutral to +0.1 (about 0.14 au), while it is too low from +0.1 to +1.0 (about 0.016 au per 0.1 charge). But the increase of the total energy of LC-wPBE(0.149) is more uniform from neutral to cation (about 0.026 au per 0.1 charge). As a result, for charge = +0.1, the total energy of the LC-wPBE(0.177) is even higher than the LC-wPBE(0.149). So it seems that the wave-function of LC-wPBE(0.177) does not correctly converge to the ground state.

The issue is solved when I use the keywords 'convergence rabuck 20 levlon 0.2'